I. Field of the Invention
The destruction of teeth by dental caries and the loss of their support through inflammatory periodontal disease is related to the activity of microbial plaque. Although differing in particulars, the relationships are essentially identical: pathogenic microorganisms become attached to a tooth, take in nutrients and liberate chemicals that are injurious to the target site, whether tooth, periodontium, or both. The attachment of organisms can be effected by growth in the sheltered areas such as the pits, fissures and faults of teeth, by self-produced adherence and colonization, such as in plaque formation, or by a combination of processes. Given sufficient nutrients and time to form toxic substances, the microorganisms will produce carious and periodontal lesions at susceptible sites.
II. Description of the Prior Art
The problem of preventing caries and inflammatory periodontal disease has been approached experimentally by attempting to interfere with plaque formation and activity and by altering tooth surfaces. Attempts to change the surface characteristics of teeth to prevent the colonization of microorganisms have not been successful. Alterations in the chemical rather than physical characteristics of the target site have been achieved to some extent by the exposure of the tooth surfaces to fluoride ions made available in water supply, dietary preparations, dentifrices, mouthwashes, topically applied solutions and gels, and restorative materials. Unfortunately, no such simple and effective agent is available to alter the soft tissues. The most successful control of plaque related to periodontal disease has been professional mechanical removal.
In rather general terms, dental plaque has been described as a tenacious, soft deposit consisting chiefly of bacteria and bacterial products. Dental plaque forms on tooth surfaces, restorations, appliances, and dentures. More precisely, plaque includes specific types of bacterial colonies surrounded by gel-like intercellular substances derived chiefly from the bacteria themselves, but also containing components from saliva and crevicular fluid, leucocites and epithelial cells. The microflora of the plaque is water insoluble and must be mechanically removed. Oral water irrigators, whether of the pulsating or steady stream type, are considered as adjuncts to the toothbrush in helping to maintain oral health but plaque being water insoluble, is not significantly removed from the tooth sites.
The brushing of the teeth and gingiva has been the home care procedure most widely recommended to promote oral cleanliness. Its basic purpose is to remove oral accumulations of plaque and debris and thereby assist in the prevention of dental disease, particularly when used with an appropriately fluoride containing, abrasive dentifrice. However, the thorough removal of dental plaque by home care procedures can be taught more easily if the plaque can actually be seen. A number of agents and techniques have been developed, some of which may be used conveniently and economically at home, whereas others may be used more effectively by the dentist at the time of instruction. The disclosing agent, erythrosine (FD & C Red No. 3), is probably the agent most frequently employed for use in the home. It has an aesthetic advantage of being a color similar to that of oral soft tissues, but it does have the disadvantage of staining any epithelial tissues, such as lips, tongue, fingers and other materials it may come in contact with, particularly cloth and sink areas. This indiscriminate staining is due to the water solubility of erythrosine and the like vegetable and organic dye products. A mixture of two dyes, again water soluble, FD & C Green No. 3 and FD & C Red No. 3, has been used and plaque appears to be differentially stained depending on age or thickness--the thicker plaque staining blue and the thinner, red. An agent such as this would be helpful in demonstrating to the patient those sites most frequently missed in cleansing procedures. Still another procedure using a colorless agent has been suggested for plaque visualization. Solutions of sodium fluorescein are essentially colorless by visible light but fluoresce strongly in light having a wave length of approximately 4800 .ANG.. Again, this procedure would necessitate special lighting equipment and is time consuming as well as economically costly.
The composition of the plaque moreover, appears to be lipoidal in nature and the interfacial tension between an aqueous dye solution or composition and the lipid is quite high. Conventional staining formulations wherein the dye is dissolved directly in water, therefore, have employed a relatively large amount of dye to circumvent this interfacial tension. As a result, excess staining of the entire oral cavity as well as non-oral objects normally results when these formulations with large dye percentages are used.